Experiments on cold nuclear fusion are performed on titanium deutende (TiD2) crystal warmed from liquid nitrogen temperature to room temperature. Fusion with an estimated thermal energy output much smaller than the expected level (1012 to 1013 fusion/s·g−1) is confirmed by neutron burst emission, but without excess heat production. By analyzing the temperature dependence of the neutron emission in the titanium-deuterium system, it is concluded that so-called cold nuclear fusion may actually be hot-spot fusion caused by a localized high voltage generated, along with fracture formation, in the TiD2 by lattice strain.